Dosing device comprising a medium reservoir and corresponding pump device

ABSTRACT

The invention relates to a dosing device that comprises a medium reservoir (S) and a pump device for dosing and dispensing a medium stored in said medium reservoir. The pump device is associated with a pump chamber, and with at least one inlet and one outlet valve. According to the invention, the inlet valve is configured as a sliding valve ( 10, 12 ) which, in its closed position, can be displaced by a dosing stroke that defines a dosing volume for the pump chamber ( 17 ). The invention further relates to the use of said dosing device for dispensing pharmaceutical active substances, especially for nasal administration.

The invention relates to a dosing device with a medium reservoir, aswell as with a pumping device for dosing and dispensing a medium storedin the medium reservoir, a pump chamber, at least one inlet valve and atleast one outlet valve being associated with the pumping device, as wellas a pumping device for such a dosing device.

DE 33 15 334 A1 discloses a dosing device provided with a pumping deviceand which is equipped with a medium reservoir for storing in particularliquid, pasty or creamy media. In addition to an inlet valve, an outletvalve and an additional outlet valve in the vicinity of an outletopening are associated with the pump chamber, the additional outletvalve being opened by means of a stepped plunger or piston through aliquid pressure which has built up within the pumping device. For thispurpose a valve body is provided and is urged into the closing directionby a spring web arrangement.

The problem of the invention is to provide a dosing device of theaforementioned type permitting a precise dosing and dispensing of amedium.

This problem is solved in that the inlet valve is constructed as a slidevalve, which is movable by means of a dosing stroke in its closedposition and this defines a dosing volume for the pump chamber. As aresult of the dosing stroke of the slide valve an extremely precisedosing is made possible. As a function of the dosing stroke lengthdifferent dosing volumes can be obtained.

According to a development of the invention, on both sides the slidevalve can be transferred into an open position over and beyond thedosing stroke, which makes it possible to bring about a particularlyprecise dosing. In addition, through the bilateral transferability ofthe slide valve into its open position a priming of the dosing device ismade possible. Thus, when the dosing device is first put into operationthe air volume in the pump chamber can be displaced, particularly intothe medium reservoir. In the direction of the medium reservoir, i.e.away from the pump chamber, the slide valve passes into the open overand beyond the dosing stroke, i.e. into its open position facing themedium reservoir.

According to a further development of the invention the dosing stroke isformed by a housing-side dosing channel matched to the slide valvecontour and which is bounded both towards the pump chamber and also themedium reservoir by in each case a cross-sectional widening. Preferablythe dosing channel is formed on a detachably positioned component. Thus,as a function of the necessary dosing volume it is possible to use asuitable component with a dosing channel of differing length. The dosingchannel length defines the dosing stroke and therefore also the dosingvolume of the dosing device. By simply replacing the component thedosing device is made suitable for different uses. As soon as the slidevalve has reached the particular cross-sectional widening, it opens, sothat in both stroke directions the slide valve can be transferred intoan open position.

According to a further development of the invention the pump chamber hasat least one housing-side reception space, with which is associated adisplacement body movable together with the slide valve and whose shapeis matched to the cross-section of the reception space in such a waythat the displacement body, on introduction into the reception space,almost completely fills the latter. This makes it possible to keep theclearance volume of the pump chamber of the dosing device extremelysmall, which further improves the dosing precision.

In a further development of the invention a pump spring arrangement usedas a return stroke drive is positioned outside the flow paths of themedium to be dispensed and in particular outside the pump chamber.Therefore the pump spring arrangement cannot be attacked by theingredients of the particular medium to be dispensed. Through the pumpspring arrangement positioned outside the flow paths of the medium it isalso ensured that there is no contamination of the medium by the pumpspring arrangement and in particular by the corrosion thereof.

According to a further development of the invention a return strokespring arrangement associated with an outlet valve body is positionedseparately from the flow path of the medium to be dispensed. Inparticular, the return stroke spring arrangement is housed in amedium-tight area separate from the pump chamber. Thus, the returnstroke spring arrangement cannot be attacked by ingredients of themedium.

Improved use possibilities are created for the pumping device in that itis designed as a subassembly manufactured separately from the dosingdevice and detachably connectable to the latter. This makes it possibleto construct the pumping device in a unitary manner and introduce itinto different dosing devices.

Further advantages and features of the invention can be gathered fromthe claims and the following description of preferred embodiments of theinvention with reference to the attached drawings, wherein show:

FIG. 1 In a longitudinal section an embodiment of a dosing device with apumping device and a pressure compensating device.

FIG. 2 Another embodiment of a dosing device with a flexible wall mediumreservoir and a pumping device similar to FIG. 1.

FIG. 3 The dosing device in FIG. 2 in longitudinal section.

FIG. 4 A larger scale representation in half-section form of a receptionunit of the dosing device according to FIG. 3 serving as a cover.

FIG. 5 A longitudinal section through a dosing device similar to FIG. 1.

FIG. 6 The dosing device of FIG. 5 with the operating handle removed.

A dosing device according to FIG. 1 has a cover 1, which can be lockedonto a medium reservoir, preferably the form of a bottle-like orcan-like container. For this purpose the cover 1 is cup-shaped and hason its inner circumference a not further designated annular shoulder,which can be locked onto a corresponding annular flange in a neck areaof the medium reservoir. In an upper area of the cover 1 is provided anot designated, circumferential, elastic seal, which is compressed onlocking the cover 1 on the medium reservoir neck and consequentlyensures a tight sealing of the medium reservoir. A cup-like receptionpart 2 is integrally shaped onto the cover 1 and projects upwardscounter to the not shown medium reservoir coaxial to a centre line axisof the cover 1. The reception part 2 forms an outer, jacket-like casingpart for a subsequently further described pumping device, which is partof the dosing device of FIG. 1. A fixed pump casing part 3 is alsoprovided integrally and projecting from the cover 1 and in factcoaxially within the reception part 2 and said part 3 is provided with adischarge channel 6 coaxially to the centre line axis of the cover 1 andsaid channel is open both downwards to the medium reservoir and upwardstowards a dosing opening 18. In a lower portion of the discharge channel6 is inserted a fundamentally known, preferably flexible suctionconnection 7. An upper portion of the discharge channel 6 is in the formof a dosing segment 13, in that said upper portion, starting from astepped taper of the discharge channel 6, constitutes a cylindricaldosing channel with a reduced diameter compared with the lower portionof the discharge channel 6. The dosing segment 13 in the form of adosing channel is surrounded by an inner cylinder jacket 4.

In radially spaced manner with respect to the inner cylinder jacket 4,the inner pump casing part 3 forms an outer cylinder jacket 5 which,like the inner cylinder jacket 4, is integrally shaped onto the cover 1.The outer cylinder jacket 5 is oriented coaxially to the inner cylinderjacket. Between the inner cylinder jacket 4 and the outer cylinderjacket 5 is left an annular displacement area 14, to which furtherreference will be made hereinafter and which forms part of a pumpchamber.

Relative to the reception part 2 fixable in secured manner to the mediumreservoir, including the inner pump casing part 3, is mounted inlift-movable or stroke-movable manner a pump unit. The stroke-movablepump unit has an outer pump casing part 8, which is firmly connected toan inner pump plunger or piston unit 9 to 11. The pump plunger unit 9 to11 is manufactured separately as an integral component and is locked inthe interior of the outer pump casing part 8. The pump plunger unit hasa plunger body 9, which forms in an upper area a cylinder space for acoaxially positioned, stroke-movable outlet valve 16. The outlet valve16 is so pressure-loaded in the closing direction by a compressionspring arrangement, here in the form of a not further designated helicalcompression spring, that the plunger-like outlet valve 16 closes theoutlet opening 18. The compression spring arrangement is placed in theinterior of the plunger-like outlet valve 16 and is supported on a baseof the cylinder space of the plunger body 9. The cylinder space of theplunger body 9 is provided in its upper marginal area with acircumferential sealing lip, which engages in circumferentially tightmanner on the outer jacket of the plunger-like outlet valve 16. As aresult the cylinder space and consequently also the reception space forthe compression spring arrangement is sealed against the penetration ofa medium, particularly a liquid. The outlet valve 16 is at the same timeconstructed as a filler, in that it almost completely fills the outerpump casing part 8. The plunger body 9 is also designed as a fillingmember, in that its outer contour is largely adapted to the innercontour of the outer pump casing part 8.

In the plunger body 9 is formed a first portion of an outlet chamber 17belonging to the pump chamber and which is open to the displacement area14 and dosing segment 13. Said first portion is radially outwardly openin its upper area and passes into an annular chamber portion of theoutlet chamber 17, which is formed between the outer jacket of theplunger body 9, the outer contour of the outlet valve 16 and the innercontour of the outer pump casing part 8. As a result of the lockingconnection of the plunger body 9 in an annular locking flange area withthe outer pump casing part 8, the annular chamber portion is axiallydownwardly closed. In the direction of the outlet opening 18, the outletvalve 16 closes the annular chamber portion of the outlet chamber 17.

In a lower area the plunger body 9 forms a coaxially inner valve plunger10, which together with the inner cylinder jacket 4 in the vicinity ofthe dosing segment 13 forms an inlet valve, in the form of a slidevalve, for the pumping device. For this purpose the valve plunger 10,which is integrally shaped onto the plunger body 9, is provided in alower area with an annular dosing lip 12, which engages tightly on aninner wall of the dosing channel forming the dosing segment 13 onintroducing the valve plunger 10 into said dosing segment 13. Thediameter of the dosing lip 12 is larger than the diameter of the valveplunger 10. The length of the valve plunger 10 and the stroke of theplunger body 9 and consequently the entire, stroke-movable pump unit aredimensioned in such a way that the dosing lip 12 in an upper openingposition shown in FIG. 1 is positioned a short distance above the dosingsegment 13. In a lower, completely downwardly pressed end position ofthe stroke-movable pump unit, the dosing lip 12 is introduced into thestepped widening of the discharge channel 6, i.e. it has moved downwardsover and beyond the dosing segment 13. As the external diameter of thedosing lip 12 is smaller than the diameter of the discharge channel 6 inthe stepped widened area and the diameter of the valve plunger 10 issmaller than the internal diameter of the dosing segment 13, in saidlower end position of the pump unit there can be a medium exchangebetween the outlet chamber 17 and the medium reservoir, via the suctionconnection 7.

Coaxially and in radially spaced manner the valve plunger 10 issurrounded by a bell-like displacement plunger 11, which by means of alower sealing edge is engaged in circumferentially tight manner on aninner wall of the annular displacement area 14. The cross-section of thebell-shaped displacement plunger 11 is adapted to the cross-section ofthe displacement area 14 in such a way that in the downwardly moved endposition of the plunger body there is virtually no clearance volume inthe displacement area, because in this position the displacement plunger11 is completely introduced into the displacement area 14. The annularspace between the outer wall of the valve plunger 10 and the inner wallof the displacement plunger 11 has its volume matched to the body volumeof the inner cylinder jacket 4, so that the remaining clearance volumeis further reduced in the case of a downwardly moved pump unit. In thevicinity of its outer jacket, the plunger-like outlet valve 16 isprovided with several annular steps, which form pressure applicationfaces for opening the outlet valve 16. The protective cap 19 has aconically downwardly widening bell shape, which is inverted over anupper shaped section of the outer pump casing part 8 and comes to restaxially on an annular shoulder ledge of the pump casing part 8. Theprotective cap is manually detachably locked onto the shaped section ofthe pump casing part 8. The external diameter of the protective cap 19is smaller than the maximum external diameter of the pump casing part 8.The upper shaped section of the pump casing part 8 is designed as a noseolive, in order to permit application to the nose of the mediumcontained in the medium reservoir. Preferably the medium stored in themedium reservoir contains at least one pharmaceutical substance.

On an outer jacket area of the outer pump casing part 8 is locked anoperating handle 20, which is provided on its top on at least twoopposite sides with in each case one finger rest. In FIG. 1 the fingerrests are provided with profiles. For axially securing the operatinghandle 20, a circumferential locking web 21 is provided on the outercircumference of the pump casing part 8 and above which is associated atleast one locking groove in which are axially engaged the correspondinginner marginal portions of the operating handle 20. The operating handle20 is preferably locked on the pump casing part 8 by means of anon-detachable locking connection, i.e. following the axial locking ofthe operating handle 20 it is no longer possible to remove it withoutdestruction from the pump casing part 8.

Below the locking web 21 the pump casing part 8 has a cylindrical guidejacket, which is provided in its lower marginal area with several stopcams 23 distributed at the same height over the outer circumference ofthe guide jacket and which cooperate with a radially inwardlyprojecting, circumferential locking collar 24 of the jacket-like orcup-like reception part 2. The locking cams 23 and locking collar 24form locking profiles, which ensure the axial securing of thestroke-moveable pump casing part 8 on the fixed reception part 2. Thelocking profiles 23, 24 axially retain the pump casing part 8 counter tothe compressive force of a pump spring arrangement 15, which serves as apump drive for the resetting of the stroke-movable pump unit into thestarting position of FIG. 1. A manual pressing down of the pump unitconsequently takes place counter to the compressive force of the pumpspring arrangement 15. As can be gathered from FIG. 1, the pump springarrangement 15 is positioned outside the outer cylinder jacket 5 of theinner, fixed pump casing part 8, so that the pump spring arrangement 15is located outside the pump area through which the medium flows. Thus,it is not possible for the pump spring arrangement 15 to be in contactwith the medium, e.g. a liquid containing at least one pharmaceuticalsubstance.

The operating handle 20 has an annular securing extension 22, which as acylinder jacket projects downwards and in the upper end position of thepump unit shown in FIG. 1 projects axially over the reception part 2 tothe extent that it overlaps the area of the locking profiles 23, 24. Thedistance from the outside of the reception part to the inner wall of theprotective extension 22 is preferably smaller than the radial extensionof the locking profiles 23, 24, so that the rigid, annular protectiveextension 22 provides a protection against a detachment of the lockingprofiles 23, 24 and therefore serves as a removal preventer for the pumpcasing part 8.

As the cover 1 in conjunction with the previously described pumpingdevice tightly seals a container serving as a medium reservoir, in thecase of corresponding pumping processes there must be a pressurecompensation in order not to impair the function of the pumping device.In the embodiment shown a pressure compensating device 25, 26, D isprovided for this purpose and is integrated into the cover 1. Thepressure compensating device has a nozzle hole D tapering in apronounced manner to the outside and serving as a pressure compensatingopening, whose narrowest diameter preferably does not exceed 0.2 mm to0.3 mm. This ensures a gas exchange, whereas a liquid loss is minimizeddue to the extremely small nozzle hole D. This leads to a reducedevaporation, which is particularly advantageous for the filterarrangement 25 additionally provided in FIG. 1. The filter arrangement25 has a not further designated reception housing for a membrane-likefilter 26. The reception housing is inserted in a correspondingreceptacle of the cover 1 and is preferably bonded into the same or isfixed thereto in some other way. The membrane-like filter 26 is extrudedround by the reception housing in the embodiment shown and isconsequently integrated into the same. It is alternatively possible tolaminate the membrane-like filter 26 on an upper front edge of thereception housing. The membrane-like filter is preferably a PP/PTFEmembrane or a TPE/PES membrane. The filter 26 serves to preventcontamination of the medium in the medium reservoir, in that theatmospheric air sucked for pressure compensation purposes through thenozzle hole D in the case of a corresponding pumping process is cleanedor purified by the corresponding membrane. Thus, the entry of water ormoisture is prevented by the filter arrangement 25.

The function of the dosing device shown in FIG. 1 will now be described.The inlet valve formed by the valve plunger 10 in conjunction with thedosing lip 12 and dosing segment 13 operates in the case of a manualoperation of the operating handle 20 as a slide, in that the outer pumpcasing part 8 together with the pump unit 9 to 11 is moved downwards.Due to the fact that in the case of a complete stroke of the pump unitthe dosing lip 12 passes downwards below the dosing segment 13 andtherefore below the stepped ledge in the discharge channel 6 into theopen, a so-called priming is made possible. This means that the air inthe pump area of the pumping device defined by the outlet chamber 17,the displacement area 14 and the annular space between the inner valveplunger 10 and the outer displacement plunger 11, during a strokemovement of the pump unit can escape downwards into the dischargechannel 6 and therefore into the suction connection 7 and mediumreservoir. During the following return stroke the corresponding suctionof the liquid medium takes place. Due to the extremely small clearancevolume within the pump area of the pumping device serving as a pumpchamber preferably a single stroke is sufficient for priming purposes inorder to bring about an adequate suction of the medium to be dispensedin the pump chamber. The length of the stroke of the dosing lip 12 alongthe dosing segment 13 defines the dosing volume. The defined dosingsegment 13 stepped in tapered manner with respect to the remainingdischarge channel 6 in conjunction with the valve plunger 10 runningdownwards into the open in slide form makes it possible, even after theend of priming, i.e. following the complete filling of the entire mediumpath in the discharge channel 6, as well as in the pumping or dosingchamber of the pumping device, a particularly accurate and reliabledosing.

A discharge process takes place as soon as the liquid pressure in thepump chamber, i.e. particularly in the upper area of the outlet chamber17, which acts on the plunger-like outlet valve 16, exceeds the counterpressure applied by the compression spring arrangement. The liquidpressure forces the outlet valve 16 downwards counter to the compressiveforce of the compression spring arrangement, so that the correspondingmedium discharge process takes place via the outlet opening 18. Theoutlet opening 18 is preferably nozzle-shaped in order to bring about anatomization of the dispensed medium. Obviously, prior to a correspondingdischarge process, the protective cap 19 is removed.

The dosing device shown in FIG. 1 comprises a few plastic components andat present of only six plastic components. A first plastic component isconstituted by the cover 1 in conjunction with the reception part 2 andthe inner pump casing part 3. The second plastic component is formed bythe outer pump casing part 8. The third plastic component is the pumpplunger unit 9 to 11. The fifth plastic component is the plunger-likeoutlet valve 16. The fifth plastic component is the operating handle 20provided with the finger rests and the final plastic component is theprotective cap 19. For assembling the dosing device firstly theplunger-like outlet valve 16 together with the compression springarrangement acting thereon is inserted in the pump plunger unit 9 andthen the latter together with the outlet valve 16 is locked in theinterior of the outer pump casing part 8, so that an upper face of theoutlet valve 16 is pressed against the corresponding valve seat in thevicinity of the outlet opening 18. Then the outer pump casing part 8,together with the pump plunger part 9 to 11, is axially inserted intothe fixed plastic component, so that locking and axial securing takeplace in the vicinity of the locking profiles 23, 24. The operatinghandle 20 is now locked axially from above on the outer pump casing part8, so that the locking connection and axial securing between the pumpcasing part 8 and reception part 2 of the cover 1 is covered andsecured. The filter arrangement 25 and circumferential seal are insertedin the cover 1. The cover 1 can then be tightly engaged on acorresponding medium reservoir. Prior to the axial engagement of theouter pump casing part 8 on the cover 1, the pump spring arrangement 15is inserted.

In the embodiment according to FIGS. 2 to 4 a pumping device Pcorresponds to the pumping device described hereinbefore relative toFIG. 1, so that for a more detailed explanation of the pumping device Preference is made to the detailed description concerning FIG. 1.Identically functioning parts are given the same reference numeralscompared with FIG. 1, but followed by the letter “a”. Details will nowonly be given of differences between the pumping device P compared withthe pumping device of FIG. 1. A description will also be given of theremaining dosing device in which the pumping device P is integrated. Theessential difference compared with the embodiment of FIG. 1 is that thepumping device P can be manufactured as a separate subassembly withrespect to the dosing device and is detachably connected thereto. In theembodiment according to FIGS. 2 to 4 the reception part 2 a isadmittedly in one piece with the inner pump casing part. The inner pumpcasing part, which is surrounded by the pump spring arrangement 15 a,together with the reception part 2 a nevertheless constitutes a unitseparate from a cover 28 for a container cup P. The cover 28 has asleeve-like or annular design and is provided with a receptiondepression into which can be locked the reception part 2 a of thepumping device P by using a circumferential annular flange. For thispurpose an edge of the reception depression is provided with an annularlocking point, which is clearly visible in FIGS. 2 and 3, but is notfurther designated. A tight, clearance-free seating of the annularflange and therefore the reception part 2 a in the reception depressionof the cover 28 is ensured by an annular seal 29, which is positionedbelow the annular flange and rests on a dish edge of the annularreception depression of the cover 28. The cover 28 is a plastic part andis locked or firmly connected by crimping to an upper marginal area ofthe container cup B.

Below the dish edge of the reception depression, the cover 28 isprovided by a profile ring 27 shaped in one piece and which as anextension to the cover 28 projects into the interior of the containercup B. As can be gathered from FIG. 4, the profile ring is provided withseveral parallel, spaced annular ribs 32, which project radiallyoutwards to a centre line axis of the cover 28. There are also severalvertical oriented rib webs extending over the height of the profile ring27 and which are not further designated in FIGS. 2 to 4. These rib websare distributed over the circumference of the profile ring 27. Thesectional view of FIGS. 2 and 3 is in each case traversed by two suchrib webs.

With respect to its pump operating function, the operating handle 20 afor pumping device P corresponds to the operating handle 20 of FIG. 1.The operating handle 20 a is additionally designed as a cup-shapedcylinder jacket, which axially engages over the container cup B by morethan half of its height. The outer jacket of the container cup B and aninner wall of a lower marginal area of the cylinder jacket 22 of theoperating handle 20 a are provided with corresponding stop profiles 30,31 which positively engage behind one another in the axial direction.This gives an axial securing action for the operating handle 20 a. Asthe operating handle 20 a, like the operating handle 20 of FIG. 1, islocked on the outer pump casing part of the pumping device P, the stopprofiles 30, 31 simultaneously create the stroke limitation for thepumping device P, which offers the necessary retaining force against thecompressive force of the pump spring arrangement 15.

The embodiment of FIG. 2 and the representation of FIG. 3 are slightlymodified. Thus, in the embodiment according to FIG. 3 the reception part2 a of the pumping device P contains a receptacle for the insertion of afilter arrangement, as shown in FIG. 1. Thus, if the cover 28 provides atight seal for the container cup B, the latter can be directly used as amedium reservoir for a corresponding liquid, because despite thedimensionally stable container cup B through the receptacle providedwith the nozzle hole, optionally with the additional insertion of afilter arrangement, there is an adequate pressure compensation duringthe operation of the pumping device P.

However, in the case of FIG. 2 there is no such pressure compensatingdevice for the container cup B. Instead the container cup B has a mediumreservoir S with flexible wall. The medium reservoir S is here in theform of a film bag produced from a one or multiple-layer film, which iscircumferentially tightly connected to the profile ring 27. Preferablythe film bag is welded to the profile ring 27 and the profiles of thelatter enlarge the surface for a tight welding of the film bag to theprofile ring 27. This ensures excellent security of the weldedconnection and a tight sealing of the film bag with the profile ring 27.The film bag serving as a medium reservoir S is consequently only opento the pumping device P, so that the same pumping and discharge functioncan be obtained as in the embodiment of FIG. 1. With each dischargeprocess there is a reduction of the volume of the medium reservoir S, sothat the film bag contracts. The flexible film bag wall consequentlypermits a pressure and volume compensation within the medium reservoir Sduring corresponding discharge processes of the pumping device P.

In the embodiment of FIGS. 5 and 6 a dosing device is shown and itspumping device corresponds to that of FIG. 1. Parts of the dosing devicehaving the same functions are given the same reference numerals as inthe embodiment of FIG. 1, but followed by the letter “b”. For furtherdetails reference is made to the description concerning FIG. 1.Hereinafter reference is made solely to the differences shown in FIGS. 5and 6. The essential difference is that the reception part 2 b, in muchthe same way as in the embodiment according to FIGS. 2 to 4 is designedseparately with respect to a cover 1 b. The cover 1 b is in the form ofa crimped cover, which can be mounted on a corresponding container neckof a medium reservoir. The mounting of the reception part 2 b togetherwith the cover 1 b in the form of a crimped cover takes placeaccompanied by the interposing of a not designated, circumferential,elastic seal. The operating handle 20 b has a cup-shaped protectiveextension 22 b, which is drawn downwards over the cover 1 b in the formof a crimped cover, so that the protective extension 22 b axially coversa crimped area of the cover 1 b in the form of a crimped cover. Thisavoids a detachment of the cover 1 b from a corresponding mediumreservoir container neck as soon as the operating handle 20 b has beenlocked on the outer pump casing part 8 b of the pumping device inaccordance with the representation and description according to FIG. 1.As the protective extension covers the crimped area of the cover 1 b,the separately manufactured operating handle is only fitted on the pumpcasing part 8 b when the cover 1 b has been crimped onto a correspondingmedium reservoir container neck, because a crimping process would not bepossible when the operating handle 22 b was already locked on.

1. Dosing device with a medium reservoir (S), as well as with a pumpingdevice for dosing and dispensing a medium stored in the mediumreservoir, a pump chamber, at least one inlet valve and at least oneoutlet valve being associated with the pumping device, characterized inthat the inlet valve is constructed as a slide valve (10, 12), which ismovable over a dosing stroke in its closed position and this defines adosing volume for the pump chamber (17).
 2. Dosing device according toclaim 1, characterized in that on both sides the slide valve (10, 12)can be transferred into an open position over and beyond the dosingstroke.
 3. Dosing device according to claim 2, characterized in that thedosing stroke is formed by a housing-side dosing channel (13) matched tothe contour of the slide valve (10, 12), which is bounded both towardsthe pump chamber (17) and towards the medium reservoir by in each case across-sectional widening.
 4. Dosing device according to claim 1,characterized in that the pump chamber has at least one housing-sidereception space (14), with which is associated a displacement body (11)movable together with the slide valve (10, 12) and whose shape ismatched to the cross-section of the reception space (14) in such a waythat, on insertion into the reception space (14), the displacement body(11) almost completely fills the same.
 5. Dosing device according toclaim 1, characterized in that a pump spring arrangement (15) serving asa return stroke drive is positioned outside the flow paths of the mediumto be dispensed and in particular outside the pump chamber (17). 6.Dosing device according to claim 1, characterized in that a returnstroke spring arrangement associated with a valve body (16) of theoutlet valve is positioned separately from the flow path of the mediumto be dispensed.
 7. Pumping device for a dosing device according toclaim 1, characterized in that the pumping device is designed as asubassembly manufactured separately from the dosing device anddetachably connectable to the dosing device.